Service valve



FIG. 1 is a front view of a service valve.

FIG. 2 is a back view of the service valve.

FIG. 3 is a left view of the service valve.

FIG. 4 is a right view of the service valve.

FIG. 5 is a top view of the service valve; and,

FIG. 6 is a bottom view of the service valve. 

The ornamental design for a service valve, as shown and described. 